1. Field of the Invention
The field of the invention is that of electrode-carrying body cavity inserts used in medical treatments.
Although the invention is generally described herein in terms of an intra-vaginal embodiment for treating urinary incontinence in women, it is not limited to that. For example, it may be employed intra-vaginally to treat other conditions in which electrical transmission to or from a body cavity may be found beneficial. It may also be found useful to be employed intra-anally in men or women to treat incontinence or other conditions.
2. Description of the Prior Art
It is known to treat female urinary incontinence with electrical stimulation applied to the walls of the vagina via electrodes carried by a probe inserted into the vagina. See, for example, Eriksen and Eik-Ness, Long-Term Electrostimulation of the Pelvic Floor: Primary Therapy in Female Stress Incontinence, 44 Urology International 90-95 (1989); Fall, Does Electrostimulation Cure Urinary Incontinence, 131 The Journal of Urology 664-667 (1984).
By activating pudendal nerve branches, such stimulation causes contraction of the muscles of the pelvic floor. Repeated sessions of such stimulation can strengthen and retrain those muscles and thereby alleviate stress incontinence in which urine passes with the onset of abdominal pressure which may result from stressed or quick activities, including sneezing and jumping. Repeated sessions of such electrical stimulation can also alleviate urge incontinence, which results from involuntary bladder contractions; the electrical stimulation apparently inhibits reflex actions of the various pelvic nerves which are responsible for bladder control.
The electrical stimulation which is supplied consists of a train of pulses. It has been found that the optimum combination of frequency, amplitude and other characteristics of these pulses differs as between individual patients and in one patient between stress incontinence therapy and urge incontinence therapy. Accordingly, vaginal inserts have been provided with two pairs of electrodes which have been powered by a pulse generator having two channels. See, e.g., U.S. Pat. No. 4,881,526 issued to Johnson and Maurer on Nov. 2, 1989. The pulse generator may be designed to allow the physician to program individualized pulse train patterns.
An electrode-carrying insert has been used in electromyographical biofeedback treatments. In those usages, the electrodes on the insert transmit electrical signals in the other direction--i.e., the electrodes detect from the vaginal or rectal wall the minute electrical impulses resulting from muscle activity and transmit those impulses to electrical components which display them to the patient. The patient utilizes the display in a biofeedback process to develop conscious and willful control over his or her muscles. U.S. Pat. No. 4,396,019, Perry, Jr., Aug. 2, 1983.
One type of intravaginal electrode-carrying insert is relatively rigid or semi-rigid and carries electrodes in the form of rings or bands around the insert. The outer surface of the insert (including both the conductive rings and the nonconductive rings which insulate the conducting rings from each other) is ideally made from a biocompatible polymer. However, effectively connecting electrical leads to conductive polymer has proven to be difficult.
Prior art body cavity inserts pose other manufacturing problems as well. Polymer inserts with alternating conductive and nonconductive rings have been made by molding conductive bands into the surface of a nonconductive polymer-carrier or by fastening conductive bands to the exterior surface of the carrier by adhesives. This manufacturing process has proven to be difficult and expensive.
In addition, manufacturing inserts to accommodate different sizes of patients may be expensive.